Devel::PartialDump(3p)

NAME
Devel::PartialDump - Partial dumping of data structures, optimized for argument printing.

SYNOPSIS
        use Devel::PartialDump;

        sub foo {
                print "foo called with args: " . Devel::PartialDump->new->dump(@_);
        }

        use Devel::PartialDump qw(warn);

        # warn is overloaded to create a concise dump instead of stringifying $some_bad_data
        warn "this made a boo boo: ", $some_bad_data

DESCRIPTION
This module is a data dumper optimized for logging of arbitrary parameters.

It attempts to truncate overly verbose data, in a way that is hopefully more useful for diagnostics warnings than

        warn Dumper(@stuff);

Unlike other data dumping modules there are no attempts at correctness or cross referencing, this is only meant to provide a slightly deeper look into the data in question.

There is a default recursion limit, and a default truncation of long lists, and the dump is formatted on one line (new lines in strings are escaped), to aid in readability.

You can enable it temporarily by importing functions like "warn", "croak" etc to get more informative errors during development, or even use it as:

        BEGIN { local $@; eval "use Devel::PartialDump qw(...)" }

to get DWIM formatting only if it's installed, without introducing a dependency.

SAMPLE OUTPUT

"foo"
        "foo"

"foo" => "bar"
        foo: "bar"

"foo => "bar", gorch => [ 1, "bah" ]"
        foo: "bar", gorch: [ 1, "bah" ]

"[ { foo => ["bar"] } ]"
        [ { foo: ARRAY(0x9b265d0) } ]

"[ 1 .. 10 ]"
        [ 1, 2, 3, 4, 5, 6, ... ]

"foo\nbar"
        "foo\nbar"

""foo" . chr(1)"
        "foo\x{1}"

ATTRIBUTES

max_length
    The maximum character length of the dump.

    Anything bigger than this will be truncated.

    Not defined by default.

max_elements
    The maximum number of elements (array elements or pairs in a hash) to print.

    Defualts to 6.

max_depth
    The maximum level of recursion.

    Defaults to 2.

stringify
    Whether or not to let objects stringify themeslves, instead of using "StrVal" in overload to avoid sideffects.

    Defaults to false (no overloading).

pairs
    Whether or not to autodetect named args as pairs in the main "dump" function. If this attribute is true, and the top level value list is even sized, and every odd element is not a reference, then it will dumped as pairs instead of a list.

EXPORTS
All exports are optional, nothing is exported by default.

This module uses Sub::Exporter, so exports can be renamed, curried, etc.

warn
show
show_scalar
croak
carp
confess
cluck
dump
    See the various methods for behavior documentation.

    These methods will use $Devel::PartialDump::default_dumper as the invocant if the first argument is not blessed and "isa" Devel::PartialDump, so they can be used as functions too.

    Particularly "warn" can be used as a drop in replacement for the built in warn:

            warn "blah blah: ", $some_data;

    by importing

            use Devel::PartialDump qw(warn);

    $some_data will be have some of it's data dumped.

$default_dumper
    The default dumper object to use for export style calls.

    Can be assigned to to alter behavior globally.

    This is generally useful when using the "warn" export as a drop in replacement for "CORE::warn".

METHODS

warn @blah
    A warpper for "dump" that prints strings plainly.

show @blah
show_scalar $x
    Like "warn", but instead of returning the value from "warn" it returns its arguments, so it can be used in the middle of an expression.

    Note that

            my $x = show foo();

    will actually evaluaate "foo" in list context, so if you only want to dump a single element and retain scalar context use

            my $x = show_scalar foo();

    which has a prototype of "$" (as opposed to taking a list).

    This is similar to the venerable Ingy's fabulous and amazing XXX module.

carp
croak
confess
cluck
    Drop in replacements for Carp exports, that format their arguments like "warn".

dump @stuff
    Returns a one line, human readable, concise dump of @stuff.

    If called in void context, will "warn" with the dump.

    Truncates the dump according to "max_length" if specified.

dump_as_list $depth, @stuff
dump_as_pairs $depth, @stuff
    Dump @stuff using the various formatting functions.

    Dump as pairs returns comma delimited pairs with "=>" between the key and the value.

    Dump as list returns a comma delimited dump of the values.

frmat $depth, $value
format_key $depth, $key
format_object $depth, $object
format_ref $depth, $Ref
format_array $depth, $array_ref
format_hash $depth, $hash_ref
format_undef $depth, undef
format_string $depth, $string
format_number $depth, $number
quote $string
    The various formatting methods.

    You can override these to provide a custom format.

    "format_array" and "format_hash" recurse with "$depth + 1" into "dump_as_list" and "dump_as_pairs" respectively.

    "format_ref" delegates to "format_array" and "format_hash" and does the "max_depth" tracking. It will simply stringify the ref if the recursion limit has been reached.

VERSION CONTROL
This module is maintained using git. You can get the latest version from <http://github.com/nothingmuch/devel-partialdump>.

AUTHOR
Yuval Kogman <nothingmuch@woobling.org>

COPYRIGHT
        Copyright (c) 2008, 2009 Yuval Kogman. All rights reserved
        This program is free software; you can redistribute
        it and/or modify it under the same terms as Perl itself.